Manufacture of artificial silk and the like from cellulose derivatives



Patented Dec. 22, 1925.,

N T D. STATES.

mnnurncrunn or lin'rrrrcrar. SILK AND rnnmxn rnou cnmioiiosn nniaivnrlvns.

1T0 Drawing.

To all whom it may concern:

Be it known that I, HENRY DREYFUS, a citizen of the Swiss Republic, of London, England, have invented, certain new and useful Improvements in or Relating to the Manufacture of Artificial Silk and the like from Cellulose Derivatives, of which the following is a specification.

This invention concerns in particular the manufacture of artificial silk or the like from solutions-of cellulose acetate, but it may also be applied for the manufacture of artificial filaments and threads from solutions of nitro-cellulose or other cellulose esters, ethers or other derivatives.

The invention relates to what is knownas the dry spinning method, that is to say to processes wherein solutions of cellulose acetate, nitrocellulose or other cellulose derivatives in solvents thereof are forced through the fine orifices of jets or spinnerets into the atmosphere to form filaments by evaporation of the solvent or medium, the filaments or threads of associated filaments being wound up on bobbins, banking-devices or otherwise. Insuch processes the filaments or threads are sometimes subjected to traction in their travel, for the purpose of draw ing them out to greater fineness. I

According to the dry spinning method as hitherto proposed the filaments are spun from solutions in solvents of relatively high volatility, such for example as solutions in acetone, methyl acetate and the like.

In spinning with such solutions, the extent to which the solidifying filaments can be drawn out for the production of filaments or threads of low deni r is limited, owing to the rapidity with wh1ch the filaments issuing from the jets or spinnerets solidify in the heated atmosphere usually employed, low temperatures involving on the other hand too prolonged setting of the filaments for I of higher boiling points, it is possible ,to derivatives the employment of s convenient manufacture in ractice.

I have now found that by incorporating in the spinning solutions a solvent or solvents vents such as referred to, other than tetrachlorethane or such like toxic chlorinederivatives'.

The boiling points of the said solvents of ENGLAND.

l p Application filcd March 10, 1922. Serial Ro- 542,752.

the cellulose acetate-or other cellulose derivative will be above that of the acetone A- EN" 31 F CE-' or other volatile solvent or liquid used therein and preferably between about 100 C. and about 150-170 C. Solvents of still higher boiling points mightbe employed in some cases, but usually this is notadvantageous, as they would cause the solidification of the filaments to take too long unless relatively high evaporation temperatures were maintained.

Some suitable higher boiling solvents for the purpose of the invention, more particularly in its application with cellulose acetate, are for example acetone-alcohol (acetyl carbinol) b. p. about 147 C., acetylacetone, b. p. about 137 0., cyclopentanone, b. p., about 130 C., diacetone-alcohol b; ,p. about 163165 'C. andcyclobutanone b'. p. 99 C.

The higher boiling solvents or solidification retarders used for the invention will be employed together with-one or more volatile solvents, such for example as acetone or methyl acetate, and in suitable proportion relatively thereto for the purpose-in view. Or organic diluents of lower boiling points than the solidfication retarding solvents may be employed instead of or together with the volatile solvent or solvents.

As-an example, spinning solutions of cellulose acetate for the purposes of the invention may consist of about parts by weight of cellulose acetate, 400- parts by weight off a volatile solvent for instance acetone, and 25 to. 50

higher boiling solvent, r example acetonealcohol, acetyl acetone,'or diacetone-alcohoL' It is to be understood, however, that the constituents and proportions may vary considerably according to circumstances or conditions without departing from the inven tion.

What I claim and desire to secure by Let- 4 I 100 of artificial threadsfication of the filaments is regulated ,andthe spinning of fine deniers facilitated.

2. In the .dry spinning of artificial threads and filaments, the employment of a cellulose fparts by weight of acetate solution comprising a volatile solvent and a liquid of higher boiling point, said liquid of higher boiling point being a solvent of the cellulose acetate and not being a, toxic chlorine derivative, whereby the solidification of the filaments is regulated and the spinning of fine dcniers facilitated.

3. A solution for dry spinning artificial threads and filaments, comprising a cellu-.

losic derivative, a volatile solvent and cyclobutanone.

4. A solution for dry spinning artificial threads and filaments, comprising cellulose acetate, a volatile solvent and cyclobutanone.

5. In the manufacture of artificial threads and filaments, dry spinning a solution of cellulose acetate containing a volatile solvent and a solvent of higher boiling point capable ofretarding solidification of the filaments and not being a toxic chlorine derivativel 6. In the manufacture of artificial threads and filaments, dry spinning a solution-of cellulose acetate containing a volatile solvent and a solvent of higher boiling point lying between about 99 and 170 0., not being a toxic chlorine derivative.

7. In the manufacture of artificial threads vments, and drawing out the filaments during the dry spinning.

In testimony whereof I have hereunto subscribed my name.

HENRY DREYFUS. 

